Physical, leaching, and toxicity characteristics of PG76 binder modified with Rediset

Asphalt binder, as one of pavement component is exposed to heat and rainfall. Polymer modified asphalt binder is a good alternative to withstand the weather in tropical countries. By utilizing warm mix asphalt additive, the high compacting and mixing temperature can be reduced. However, the impact to the environment and its characteristic towards high temperature need to be evaluated before putting it to use. In the study, the physical properties, thermal characteristics, and leaching and toxicity of PG76 incorporated with Rediset LQ were investigated. The Tank Leaching Test was carried out to mimic the worst scenario of flood event effect on the asphalt binder. The results of physical tests denote that the new material has relative consistency while the thermal analysis indicates that the materials are stable beyond their mixing and compaction temperature. The decomposition starts at temperature > 360°C and ends at temperature <500°C for all samples. The tank leaching test also found that the materials are safe to be used as pavement material because the heavy metal elements from the leachate are below the maximum allowable volume by the World Health Organization and the United States Environmental Protection Agency.

Leachability of Fired Clay Bricks Incorporated with Sewage Sludge by Using Tank Leaching Test

This research was conducted to fully utilize the sludge that rich in dangerous heavy metals and at the same time act as low cost alternative materials in brick manufacturing. Different series of sludge and clay proportioning ratios were studied, which exclusively involved the addition of sludge with ratios of 0, 1, 5, 10, 20 and 30% of the total weight of sludge-clay mixture. Each molded brick were oven-dried at 105˚C for 24 hours followed by heating at 1050˚C. The investigation includes determination of heavy metal concentration of the sludge and clay using XRF and heavy metals leachability of the bricks by using Tank Leaching Test according to NEN7345 that has been analyzed by using ICPMS. The leaching behavior of several heavy metals (As, Ni, Cu, Pb, Zn, V, Ba, and Cr) from incorporated sludge into fired clay bricks shows to be insignificant and far below the USEPA regulations limits which fulfill the general requirement for usage of clay brick in construction and comply with the leaching standard limit. As a conclusion, the utilization of sewage sludge can reduce the disposal to landfill and reduce the leachability of sludge which can effect environment and human.